The "plum" coloration is sometimes seen on firearms (not just Lugers) which have been salt-blued. It is the result of chemical contamination or temperature variation in the salt-blue cheical bath.
"Pluming" is not the result of wear or differential storage. Artillery Lugers were originally rust-blued, and so not subject to this phenomenon. Plum-color parts on an artillery Luger are an indication that the parts have been reblued in a salt-bluing solution.
--Dwight
|